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24 Cards in this Set

Skin has a low requirement for oxygen, so why does it have such a rich blood supply?

So that body temperature can be well regulated

If perfusion of the brain is compromised, what reflex occurs? How does it help?

'Cushing reflex' (increased sympathetic drive)

It maintains/increases arterial blood pressure

Which type of vasodilator fibres innervate the sweat glands? Why is this important?

Cholinergic sympathetic vasodilator fibres.

Important as bradykinin (a vasodilator) is produced by sweatglands

What is bradykinin?

A vasoDILATOR (also contracts skeletal muscle)

1838300111 Weekend with Jess after 3 weeks :)

Is bradykinin a vasoconstrictor or vasodilator? Where is it produced?

Vasodilator produced by sweat glands

The right coronary artery *principally* supplies which chambers?

RA and RV (apart from a strip of RV, it also supplies a strip of the LV)

The left coronary artery *principally* supplies which which chambers?

LA and LV (and strip of LV, it also supplies a strip of the RV)

Where does the cardiac vein drain into? (Chamber and special name)

Drains into the coronary sinus in the right atrium (NB do not confuse with coronary sulcus, which is a groove where some coronary vessels travel)

When is blood flow to the myocardium at its peak? Why then? It's something to do with aortic pressure

Early diastole. Mechanical compression of coronary vessels is minimal and aortic pressure is still high

When is coronary blood flow at its minimum? Why?

During the isovolumetric contraction phase of the cardiac cycle. This is because the coronary blood vessels become compressed as the ventricular pressure rises

How is the increase in coronary blood flow during increased exercise thought to be brought about? Which chemical?

Release of the vasodilator 'adenosine'. Production of adenosine increases during increased workload.

Sympathetic nerve supply to coronary arteries is highly important in the control of coronary blood flow T/F

F (however, it does cause some vasodilation)

What is the most important determinant of coronary blood flow? I.e. what stimulates it to increase?

Metabolic hyperaemia (the increase of blood flow to different tissues in the body)

The cutaneous (related to the skin) vessels are innervated with vasodilatory parasympathetic nerve fibres T/F

F - AV anastomoses and arterioles are innervated by sympathetic fibres only - causing constriction when stimulated, and reduction of stimulation leads to vasodilation

Which two arteries supply the brain?

The internal carotid and vertebral arteries

Why would it be infeasible to increase blood flow to the brain, even if desired?

The brain is enclosed by the skull, swelling (caused by increased blood flow) could cause damage. Any change in the volume of blood flowing to the brain must be matched by a change in the venous outflow

Is regional functional hyperaemia well developed in the brain? How so?

Yes, an increase in neuronal activity evokes a local increase in blood flow (Sorry for poor question)

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What is an important clinical indicator of a space-occupying lesion within the skull?

Rise in blood pressure (Cushing's reflex) and fall in heart rate

Are lipid soluble, or ionic solutes freely able to pass from the blood to the interstitium of the brain?

Lipid soluble compounds

Which area in the brain forms CSF?

The choroid plexus (~500ml per day (NB there is only ~350ml of CSF at any one time))

At which vertebra is a lumbar puncture taken? Why doesn't it damage the spinal cord?

Between the third and fourth lumbar vertebrae. Tip of needle lies in subarachnoid space, spinal cord extends only as far as the first lumbar vertebra

What are the two main functions of CSF?

Hydraulic buffer to cushion the brain against damage resulting from movements of the head

Helps provide a stable ionic environment for neuronal function (it is in direct contact with the extracellular fluid of the brain)

What is hydrocephalus?

In babies and young children, where the skull structures are not fused, an increase in intracranial pressure leads to a disproportionate increase in the size of the head. This is known as 'hydrocephalus'

What is the effect of hypercapnia on blood flow to the brain?

It results in increased blood flow (NB this will be matched with an increase in venous return)

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